Pharmacology: Lifespan Considerations. Chapter 3

May alter absorption of drugs that require acidity to dissolve.

An older patient will often experience a reduction in the stomachs ability to produce gastric acid. The nurse knows that this change:

Parkinson's disease

Antipsychnotics, phenothiazines

4 weeks (first trimester)

At which gestational age does an embryo or fetus have the highest risk for drug-induced developmental defects as a result of teratogenic exposure? -Greatest risk for drug induced developmental defects.

Older Adults Medication Administration Considerations

-Age -Allergies to drugs and food -Dietary habits -Sensory visual, hearing, cognitive, and motor skill deficits -Financial status and any limitations -List of all health related care providers -Listing of medications -Existence of polypharmacy -Laboratory test results -History of smoking and use of alcohol -Risk situations related to drug therapy identified by the Beers criteria ***

Last Trimester

-Drug transfer to the fetus bc of enhanced blood flow to fetus -Greatest percentage of maternally absorbed drug gets to the fetus.

Older Adults Absorption

-Gastric pH is less acidic bc of gradual reduction on the production of hydrochloric acid in the stomach -Gastric emptying is slowed bc of a decline in smooth muscle tone and motor activity. -Movement in GI tract is slower because of decreased muscle tone and motor activity. -Blood flow to the GI tract is reduced by 40% to 50% bc of decreased cardiac output and decreased perfusion. -The absorptive surface area is decreased bc the aging process blunts and flattens villi.

Pediatrics Absorption

-Gastric pH is less acidic until 1-2 years of age bc acid-producing cells in the stomach -Gastric emptying is slowed bc of slow/irregular peristalsis. -First-pass elimination by the liver is reduced bc of the immaturity of the liver and is reduced levels of microsomal enzymes. -Intramuscular absorption is faster and irregular.

Pediatrics Excretion

-Glomerular filtration rate and tubular secretion and resorption are all decreased in young patients bc of kidney immaturity. -Perfusion to the kidneys may be decreased, which results in reduced renal function, concentrating ability, and excretion of drugs.

Older Adults Excretion

-Glomerular filtration rate is decreased by 40% to 50%, primarily because of decreased blood flow -Number of intact nephrons is decreased (leads to decreased rate of excretion and risk for build up of drugs in system resulting in potential for drug toxicity)

Pediatric Distribution

-Greater total body h20, the lower the fat content -Total boy water: 70%-80%= Full term infants 85%= premature newborns 64%=1-12 year children -Protein binding is decreased bc of decreased production of protein by the immature liver. (this can result in drug toxicity) -More drugs enter the brain bc of immature blood-brain barrier.

Older Adults Distribution

-In adults: 40-60 years of age, total body water is 55% in males and 47% in females. those older than 60 years of age is 52% in males and 46% in females. -Fat content is increased bc of decreased lean body mass. -Protein (albumin) binding sites are reduced bc of decreased production of proteins by the aging liver and reduced protein intake. (this can raise the risk for drug toxicity)

Pediatrics Drug Administration Considerations

-Mix medication in a substance other than essential foods. (spoonful of ice cream or pudding- non-essential foods). vs milk, orange juice, or cereal which is essential foods. -Do NOT ass drugs to fluid in a cup or bottle -Document special techniques of drug administration -Unless contraindicated, may add small amounts of water to elixirs to make more palatable -Avoid using the word "candy" for medicine -Keep all medicines out of reach of children -Ask family how child usually takes medication (preference of pill vs. liquid, etc.)

Older Adults Metabolism

-The levels of microsomal enzymes are decreased bc the capacity of the aging liver to produce them is reduced. -Liver blood flow is reduced by approximately 1.5% per year after 25 years of age, which decreases hepatic metabolism.

Pediatrics Metabolism

-the levels of microsomal enzymes are decreased bc the immature liver has not yet started producing enough -Older children may have increased metabolism and require higher dosages once hepatic enzymes are produced. -Many variables affect metabolism in premature infants, and children, including the status of the liver enzyme production, genetic differences, and substances to which the mother was exposed during pregnancy.

"Studies indicate that there is no risk to the human fetus, so it is okay to take this medication as directed if you need it."

A pregnant patient who is at 32 weeks gestation has a cold and calls the office to ask about taking an over-the-counter medication that is rated as pregnancy category A. Which answer by the nurse is correct?

First Trimester

A woman who has just discovered that she is pregnant is asking the nurse about taking medications. The nurse keeps in mind that the greatest risk for drug-induced developmental defects occurs during which trimester of pregnancy?

Anticoagulants

Heparin and Warfarin (coumadin) -major and minor bleeding episodes, many drug interactions, dietary interactions

Category D

Possible fetal risk in humans has been reported; however, in selected cases consideration of the potential benefit versus risk may warrant use of these drugs in pregnant women.

Category B

Studies indicate no risk to the animal fetus; info for the humans is not available.

Category A

Studies indicate no risk to the human fetus

Water composition of approximately 75%

The physiologic differences in the pediatric patient compared with the adult patient affect the amount of drug needed to produce a therapeutic effect. The nurse is aware that one of the main differences is that infants have?

-Increased gastric pH -Increased body fat -Decreased hepatic mass

When considering the physiologic changes that affect pharmacokinetics in the elderly, the nurse recognizes that what occurs?

Insomnia

Decongestants, bronchodilators, monoamine oxidase inhibitors

Thiazide diuretics

electrolyte imbalance, rashes, fatigue, leg cramps, dehydration

Central Nervous System (CNS) Depressants (muscle relaxants/opioids)

sedation, weakness, dry mouth, confusion, urinary retention, ataxia

Syncope/ Falls

sedatives, hypnotics, opioids, CNS depressants, muscle relaxants, antidepressants, antihypertensives

12 months (1 year of age)

When considering the effect of renal function on drug excretion, the nurse recalls that adult levels of renal function are achieved by what age?

-Drug properties -Fetal gestational age -Maternal factors

3 Factors affecting safety during pregnancy

The nurse prepares to administer a drug that is absorbed in the stomach to an older adult patient. Drug absorption in this patient is likely to be what? A. Increased as a result of diminished peristalsis B. Increased by altered portal blood flow C. Slowed as a result of excessive gastric acidity D. Slowed as a result of delayed gastric emptying

A. Increased as a result of diminished peristalsis Many factors can alter the absorption of drugs in older adults. The delayed gastric emptying associated with diminished peristaltic action can increase absorption of a drug that is absorbed in the stomach because the delay exposes the gastric mucosa to the drug for a longer period. Altered portal blood flow affects drug distribution, and older adults tend to have less gastric acid secretion.

Which information does the nurse use to calculate a pediatric drug dose on the basis of the patient's weight? (Select all that apply.) A. Patient's weight in kilograms B. Amount to be administered per day C. Drug order from the prescriber D. Minimum daily dose for the patient E. Guidelines from the drug formulary F. Usual 24-hour dose range

A. Patient's weight in kilograms C. Drug order from the prescriber E. Guidelines from the drug formulary F. Usual 24-hour dose range The nurse uses the patient's weight in kilograms to calculate a pediatric dose because weight-based dosage calculations are given in milligrams per kilogram of body weight. The nurse also uses the drug order from the prescriber as a critical variable in the equation because the order establishes the amount of the drug per kilogram of the patient's weight that should be administered. After calculating the 24-hour dose, the nurse compares it to the dose range from the formulary to ensure that the prescribed dose falls within the recommended range. The minimum daily dose is a part of the 24-hour dose range.

Which characteristics of an infant does the nurse assess to control drug absorption as a means of helping prevent adverse drug effects? (Select all that apply.) A. Skin integrity B. Liver enzymes C. Serum albumin D. Drug properties E. Peristaltic action F. Serum creatinine

A. Skin integrity D. Drug properties E. Peristaltic action The nurse assesses characteristics of the infant because delayed or accelerated drug absorption can affect the onset of drug action and the infant's exposure to the drug's effects. The nurse assesses the skin because an infant's skin is thinner than an adult's and can absorb topical medication more readily. Drug properties, including the drug's chemistry or concurrently administered drugs, can affect drug absorption as well. Peristaltic action is assessed because slow peristalsis can increase absorption if the drug is absorbed in the stomach or the intestines. Liver enzymes affect biotransformation, serum albumin affects distribution, and renal function affects drug elimination.

Category C

Adverse effects reported in the animal fetus; information for humans is not available

Ask the patients wife to bring his medications to the hospital in their original containers.

An 82 year-old patient is admitted to the hospital after an episode of confusion at home. The nurse is assessing the current medications he is taking home. What method is the best way to assess home medications.

A medication that diffuses across the placenta

The nurse wants to minimize fetal exposure to drugs in a patient who is 26 weeks pregnant. Which type of medication warrants nursing verification of adequate maternal renal and kidney function?

The nurse plans care for an older adult male patient with a complex drug regimen. Which action should the nurse implement to decrease the risk of patient nonadherence to therapy? A. Instructing the patient to call for information about the drug therapy B. Providing the patient with written instructions for all drugs prescribed C. Encouraging the use of multiple alarms for drug reminders D. Suggesting home remedies to counteract adverse effects

B. Providing the patient with written instructions for all drugs prescribed To decrease the risk of patient nonadherence to a complicated drug regimen, the nurse provides written instructions for all drugs that the patient takes and tries to simplify the regimen. Written instructions provide the patient with a reliable reference and a reminder for self-administration at home, and the regimen is simplified when the nurse compiles the information into a single medication schedule. The nurse breaches the duty owed to the patient by delegating proper instructions to the patient; telephone-based support or source of reference is suitable once drug therapy instructions have been delivered properly by the nurse. The use of multiple alarms increases the complexity, as well as the potential cost, of an already complex situation. The nurse instructs the patient to avoid home remedies and over-the-counter medications without the prior approval of the prescriber.

A malnourished older adult patient experiences drug toxicity. Which factor does the nurse assess to rule out drug distribution as a cause of the patient's toxicity? A. Drug dosage B. Drug half-life C. Gastric acidity D. Plasma proteins

D. Plasma proteins A malnourished older adult is likely to have a smaller percentage of lean muscle and lower levels of circulating plasma proteins. The result is fewer protein-binding sites, increased serum drug levels, and intensified drug effects. An error in drug dosage is a prescribing error, the half-life is an issue of metabolism, and gastric acidity involves drug absorption.

Anticholinergics

Blurred vision, dry mouth, constipation, confusion, urinary retention, tachycardia

Decreased GI motility

When considering drug dosages for the older adult, the nurse recognizes that which is an age-related change that may affect pharmacokinetics?

Which factors contribute to a higher incidence of adverse drug reactions in older adult patients? (Select all that apply.) A. Increased incidence of falling B. Increased fibrosis of liver C. Decline in organ function D. Complexity of therapy E. Slower filtration in kidneys F. Higher drug levels in serum

C. Decline in organ function D. Complexity of therapy E. Slower filtration in kidneys Adverse drug interactions are more common in older adult patients than in younger ones because organ function declines slowly with age, drug therapy for older adults tends to be more complex, and glomerular filtration in the kidneys is slower. Adverse drug reactions contribute to an increased incidence of falls, liver fibrosis is not common in older adults, and the older adult is at risk for higher circulating drug levels if the patient is hypoalbuminemic.

Which knowledge about older adult patients in relation to younger ones does the nurse apply before administering a medication? (Select all that apply.) A. Superior drug therapy adherence B. Less prescription drug sensitivity C. Higher incidence of self-medication errors D. Higher incidence of adverse drug reactions E. Lower risk of drug-drug interactions F. Altered pharmacokinetic processes

C. Higher incidence of self-medication errors D. Higher incidence of adverse drug reactions F. Altered pharmacokinetic processes Because older adult patients are more likely to have complex drug regimens and to be subject to polypharmacy, they are more likely to commit self-medication errors and are at a higher risk for adverse drug effects. This is especially true of an older adult with impaired sensory, cognitive, or motor function. Older adults are likely to have altered pharmacokinetics and altered sensitivity to drugs as a result of declining organ function and drug-drug interactions. Older adults do not necessarily adhere to therapy regimens better than younger adults do, and they are at higher risk for drug-drug interactions because older adults tend to take more medication than younger adults do.

Chroni Constipation

Calcium channel blockers, tricyclic antidepressants, anticholingerics

Category X

Fetal abnormalities have been reported, and positive evidence of fetal risk in humans is available from animal and/or human studies. These drugs are not to be used in pregnant women.

Opiods/ Analgesics

Confusion, constipation, urinary retention, nausea, vomiting, respiratory depression, falls

The nurse checks the dosage calculation of a medication that acts on the central nervous system (CNS) for accuracy before administering the drug to an infant. Why does the nurse check the calculation? A. Infants have slower drug metabolic rates. B. Infants have adequate serum protein levels. C. Infants have wide fluctuations in their weight. D. Infants have immature blood-brain barriers.

D. Infants have immature blood-brain barriers. The blood-brain barrier is not fully developed at birth; because of this, drugs enter the CNS more easily, thereby rendering the infant especially sensitive to drugs that affect CNS functions such as respiration. Because the nurse bases dosages on infant weight, the nurse calculates the dosage at regular intervals to ensure the proper dosage of a given medication for the infant's current weight. The metabolic rate of an infant is affected by many factors, and it is not necessarily inadequate. Because of immature hepatic function, the levels of plasma proteins produced by the liver are likely to be lower than they are in an adult. Finally, an infant's weight may vary, and such variation can necessitate a significant change in dosage; however, the weight variation is more likely to be a small one.

Clotting disorders

NSAIDs, aspirin, antiplatelet drugs

Drug half-life is lengthened

When considering the age-related changes in the kidney of the older adult, the nurse recalls that which drug response is possible?

breastfed infants are at risk for exposure to drugs consumed by the mother Risk-to-benefit ratio depends on how much breastmilk the baby consumes

Drug therapy during breastfeeding

Non-steroidal anti-inflammatory drugs (NSAIDs)

Edema, nausea, gastric ulceration, bleeding, renal toxicity

Microsomal Enzymes

Enzymes in liver cells responsible for metabolizing exogenous substances such as drugs.

chronic obstructive pulmonary disease (COPD)

Long acting sedatives or hypnotics, narcotics, beta blockers

Body weight in kilograms

Most drug references provide recommended pediatric dosage based on what?

On body weight and organ function

The nurse recognizes that drug dosages in older adults are based on what?

Antidepressants

Sedation and strong anticholinergic adverse effect (blurred vision, dry mouth, constipation, confusion, urinary retention, tachycardia)

-Provide a brief, concrete explanation about the injection. -Make use of magical thinking. -Provide comfort measures after the injection.

The nurse is preparing to administer an injection to a preschool-age child. Which approaches are appropriate for this age group?

Immature renal system

The nurse is reviewing factors that influence pharmacokinetics in the neonatal patient. Which factor puts the neonatal patient at risk with regard to drug therapy?

Distribution of the drug

The nurse prepares medication for a 24-year old patient who is 30 weeks pregnant and has hypoalbuminemia. Which factor related to drug safety in pregnancy is the nurses's priority to reduce the risk of excessive drug exposure to the fetus when planning care for this patient?

Polypharmacy

The use of many different drugs concurrently in treating a patient, who often has several health problems.

Cardiac Glycosides (Digoxin)

Visual disorders, nausea, diarrhea, dysrhythmias, hallucinations, decreased appetite, weight loss

Creatinine Clearance

When evaluating renal function in the elderly, the nurse knows that the best indicator of renal function is?

-The ratio of fat to water content is increased -Gastric pH is less acidic because of reduced hydrochloric acid production -Protein albumin binding sites are reduced because of decreased serum protein

When giving medications to older adults, the nurse will keep in mind the changes that occur due to aging. Which statements apply to the changes in older patients?

Antihypertensive

When the nurse is reviewing a list of medications taken by an 88-year-old patient, the patient says, "I get dizzy when I stand up." She also states that she has nearly fainted "a time or two" in the afternoons. Her systolic blood pressure drops 15 points when she stands up. Which type of medication may be responsible for these effects?

Slow, irregular peristalis

Which factor relate to normal infant physiology is most likely to affect the onset of action for an oral medication absorbed in the intestines of a 4-month old infant?

Immaturity of the organs

Which factor would have the greatest effect on medication response in the newborn?

-Unpleasant side effects -Believing that the prescribed dose is not needed

Which factors contribute to intentional noncompliance in the elderly?

Takes multiple medications for several different illnesses.

While assessing the medications taken by an elderly woman, you determine that she is experiencing polypharmacy. This indicates that:

Decreased blood flow to the liver, resulting in altered metabolism

While teaching a 76-year old patient about the adverse effects of his medications, the nurse encourages him to keep a journal of the adverse effects he experiences. This intervention is important for the older adult patient because of which alterations in pharmacokinetics ?

Bladder flow obstruction

anticholinergics, antihistamines, decongestants, antidepressants

Sedatives and Hypnotics

confusion, daytime sedation, ataxia, lethargy, increased risk for falls

Antihypertensives

nausea, hypotension, diarrhea, bradycardia, heart failure, impotence

Heart Failure and Hypertension

sodium, decongestants, amphetamines, over the counter cold products

Diffusion

this is how drugs cross the placenta

Immaturity of neonatal organs

which physiologic factor is most responsible for the differences in pharmacokinetic and pharmacodynamic behavior of drugs in neonates and adults?